An averaging two-electrode probe for monitoring changes in myocardial conductivity evoked by ischemia

Abstract

This paper considers the applicability of effective conductivity measurements for monitoring physiological and/or pathological phenomena induced by ischemia in the myocardium. The sensitivity of a probe, calculated by means of the finite element method, to changes in the conductivity of the tissue examined is defined for this purpose. Probes developed by Schafer and collaborators (1995) and in our own departments have been examined on the basis of this sensitivity. Theoretical results were verified experimentally using a tank, enlarged models of the probes, and a specially developed electronic circuit. It follows from this study that the probe developed by Schafer et al. is characterized by positive and negative sensitivity. This can lead to misinterpretation of the measurements obtained. In contrast, the sensitivity of our probe is dominantly positive. An example of the in vivo result obtained during experimentally induced ischemia in a swine heart is included.

Assessment of Cardiovascular Risk in Assisted Living

“…The experimental evaluation of the sensitivity approach has been validated in this paper and previously in [25,26]. Thus, the methods used and results obtained can be considered as reliable.…”

Free Myocutaneous Flap Assessment in a Rat Model: Verification of a Wireless Bioelectrical Impedance Assessment (BIA) System for Vascular Compromise Following Microsurgery

“…Therefore, continuous monitoring can reduce the flap failing rate. Some devices have been developed for continuous monitoring of tissue flaps after surgery, guts perfusion and myocardium by measuring microvascular parameters [ 11 , 13 , 17 , 18 ].…”

“…Bioelectrical impedance analysis (BIA) has been developed to evaluate changes in human tissue composition and animal experiments [ 11 ]. The basic concept of BIA is to inject a current with different frequencies into the tissue to estimate the whole bio-impedance of the human tissue, which is contributed to by the bio-impedances of the different human tissue components [ 12 , 13 ].…”

Optimization of a probe for the spectroscopic electrical characterization of biological tissues

“…At the scale of the measurement probe, this element can be considered as surface impedance and can be taken into account in the finite element model using an impedance condition [10] [17]:…”